"Glenn Ashmore" wrote in message
news:7vhgd.80763$hj.25297@fed1read07...
Actually you only need 800 PSI

You can certainly do it with far less than that. A home RO unit runs off the
water line pressure, which is usually less then 75 PSI.

which is still way past what a ram pump can produce.

There are always ways to convert a flow of water and one pressure to a
lesser flow at higher pressure. You might have better output running a
solar still, however.

There is a tow behind RO watermaker called the Waterlog that uses
a small mechanical pump powered by a propellor.

There are a lot of instances of a towed electrical generator. It certainly
would not be conceptionally difficult to convert it into a water pump. I
can picture a small prop on a steel cable that runs up to a gear box on the
transom rail. Enough gear ratio can turn the spinning cable into sufficient
torque to generate just about any PSI you wanted.

I would think that you would be better off to just generate electricity and
then run the standard electric pump. Perhaps not as efficient, but much more
versatile.

Rod